Weft-inserting devices for continuousfeed looms



R. DEWAS April 4, 1967 WEFT-INSERTING DEVICES FOR CONTINUOUS-FEED LOOMS Filed Maoh lO, 1964 ll llmw|||l |||l llllwlllwwr, lllllllll liL United States Patent() 4 Claims. (l. 139-122) The invention relates to weft-inserting devices for looms with continuous weft feed from large bobbins situated outside the shed. It relates to inserting devices comprising a weft thread gripping device with an elastic clamp, which is opened, in order to release the thread, by a blade which moves the clamp members apart. The elastic clamp of this gripping device consists of a rigid member and a resilient member, the rear part of which has a foot portion generally affixed to the rear portion or seating portion of the rigid member.

The front part of the resilient member is provided, at its edge opposite the fell of the cloth with a tooth forming a hook adapted to grip the weft thread, while at its edge facing the reed side it is provided with a wing which extends downwards and towards the rear, beyond the zone comprising the hook. Due to the existence of this wing the front part of the -resilient member has the shape of an angle and is thus rigid, while the remainder is flexible and springy.

Due to the relatively great length of the flexible portion of the resilient member, its adjustment is an extremely delicate operation.

Furthermore, the progressive raising of the resilient member by the release blade causes, due to tension release, a straightening of the front resilient part, i.e. that part which is included between the contact point of the resilient member and the beginning of the angle; this results, owing to the reduction of the curvature, in a considerable inclination of the bottom of the resilient member in respect of the large surface of the release blade; over a certain distance, therefore, the said blade only operates by its fore extremity, and thus with an increased pressure per unit area, which, owing to the localized temperature rise, causes deterioration of the said release blade. Since, moreover, as soon as the extremity of the blade has passed, those parts of the resilient member which have just been deprived of their strains, either Wholly or partially, are once again subjected to exure, with greater stresses than before, the same phenomena are repeated, in the reverse order, after the direction of motion of theclamp has been reversed, and considerable intermolecular work takes place, prejudicial to the internal equilibrium of the metal and adding t-o the temperature rise. Owing to the repetition, at an increased rate, of the movements on the blade, and the shrinkage, this temperature rise may reach a level liable to detract from the elastic properties of the metal. Furthermore, a certain strain-hardening of the metal, on the surface which rubs against the blade, may result in an alteration in the shape of the resilient member, owing to the limited thickness of this latter.

These various effects reduce the accuracy of adjustment.

Finally, the aforementioned reduction in the curvature results, in the clamping zone, in a slight forward displacement of the front extremity of the resilient member on the rigid member, and this in turn causes the two surfaces to suffer wear, by contact with each other.

Reverting to the angle of inclination assumed by the front part of the resilient member, during the movement of the blade, it can easily be understood that this leads,

l, Patented Apr.,4, 1967 ICC in the clamping zone, to the commencement of an opening movement at the rear before ascent takes place; this is a factor liable to cause irregularity in the release of the wefts, particularly in the case of irregular wefts, or very coarse wefts alternating with fine wefts, all the more so since, with this type of clamp, the separation of the rigid member from the resilient member takes place comparatively slowly.

The purpose of the invention is to remedy these drawbacks, and it consists, in general, of a structure in which the greater part of the resilient member rearwardly of the angle, is rendered rigid, the said member nevertheless retaining the required elasticity to enable it to perform its function correctly.

For this purpose, according to the invention, the flexible part of the said member is conned to a short portion which precedes the foot portion, so that the resilient member comprises, in combination, a rigid portion which extends from its front extremity, formingva point, to a short distan-ce from the foot portion and then a flexible resilient portion which precedes the foot portion, and finally the foot portion intended to be secured to the rigid member which also advantageously may be rigid.

In such a structure therefore,.the flexible resilient portion of the resilient member is limited to a portion preceding the foot portion. In other words, the resiliency of the member, instead of extending over the entire length included between the end of the Vangle and the foot portion, is confined to the portion located in the vicinity of the said foot portion, so that the ascending and descending movements of the resilient member are very close to those which would be carried out by a part hinged on ay shaft in the vicinity of the foot portion.

This new design results in numerous advantages:

The optimum setting and adjustment are produced more easily.

The pivoting effect of the lrigid part of the resilient member, when the clamp moves forward on the release blade, causes the bottom of the resilient member to present itself at an angle of incidence more favourableto the penetration lof the blade, and the increase in the contact surface area between the blade and the resilient member is brought about more rapidly, and with a more satisfactory distribution of the pressures; this results in a Ilower temperature rise, since practically no deformation takes place in the rigid portion, so that'there is no intermolecular work, and since the heat set up by the friction is diifused in the greater metallic mass of the rigid portion.

For the same reasons, the release blade undergoes less wear.

The rigid part of the resilient member being obviously not subjected to deformations and, moreover, ascending a shorter time after having engaged the release blade, the above-mentioned relative longitudinal motion is practically nil in the clamping zone, and causes no wear to take place in the said zone.

The opening of the clamp occurs more rapidly and with a iblade position farther away from the clamping zone; this results in greater regularity in the release of the weft thread and enables the position of the blade to be adjusted with greater ease.

These characteristics and advantages will `be clearly understood from the following description of one embodiment of the invention, described solely by way of an example, without any limitative effect, and shown schematically in the accompanying drawings, in which:

FIG. l is an elevation, on the side facing the fell, of an improved insertion device having a clamp in accordance with the invention;

FIG. 2 is a plan view;

FIG. 3 is an elevati-on, on a larger scale, solely of the resilient member, on the side facing the fell and shown in the operating position as in FIG. 1.

In these drawings, 1 is the entire rigid member of theinsertion device and 2 the entire resilient member; 3 is that part of rigid rne'mber 1 which forms a seating portion, to which the resilient member is afiixed by means of screws 4; 5 is the point of the resilient member, 6 the hook, 7 the wing forming an angle iat the end portion of the resilient member, 8 the release blade, and 9 the clamping zone of the weft thread.

According to the invention, the resilient member comprises, starting from its front extremity which forms a point 5, a long rigid portion 2a, having an extension in the form of a short resilient part 2b which preceeds the foot portion 2c aixed to the seating portion 3. In this constructional version the rigidity of portion 2a is retained, starting from the point 5, firstly by the presence of the wing forming an angle 7, and then, at a certain distance d behind the hook 6, in order not to impede Vthe action of the hook 6 taking up the weft thread, but

before the end of the angle 7 and on the opposite side of member 2 by a considerable increase in thickness beginning Kat slanting portion 2d of the resilient member 2.` In the vicinity of the seating portion 3 the thickness of resilient member 2 is once again reduced, with slanted portions 2e and 2f between the sections 2a and 2c of greater thickness being directed inwardly so as to produce the short resilient portion 2b. It is of advantage for the thickness of the blade to be increased in the foot portion 2c which is affixed to the seating portion 3, the slanted portion 2f between these two parts of different thickness being provided on the external face of the resilient member. This additional thickness of the part 2c enables the xing to be carried out without recourse to the backing plate hitherto employed.

Slanted portion 2e is provided on the face of the resilient member which eng-ages seating portion 3. It is thus apparent that the resilient member 2 is composed of three successive main portions, namely, a rigid foot portion 2a, a resilient portion 2b and a rigid portion 2c, as indicated in -FIGURE 3.

When the insertion device emerges from the shed and the rigid portion 2a of the resilient member 2 contacts the release blade 8, this latter, after penetrating to a slight distance between the rigid and the resilient members, separates the contacting surfaces 1a and 6a of these two members which constitute an elastic clamp in the clamping zone 9, by causing the resilient member to ascend more rapidly, as a result ofthe pivoting eiieet caused by the hinge-like resilient portion 2b, than in the form of construction provided for in previous embodiments; it will easily be understood that this rapid opening action results -in a more uniform release action, and thus in a more accurate positioning of the weft ends, enabling the length of these latter to be reduced t-o the minimum, the amount of waste being therefore likewise reduced.

Furthermore, the release action being brought about while the release blade is at a greater distance from the point 5 of the resilient member and thus from the weft end, it follows that, for a given weft end position, the position of the release blade is farther away from the selvage, thus providing more room to t-he various devices which may be situated in the vicinity of the said salvage.

Finally, since the release blade undergoes less wear, less frequent action is required f-or adjusting the position of the weft ends, and this results in a saving of labour and in a further reduction in the amount of wastage.

Needless to say, the invention is not confined to the embodiment described and illustrated, and modifications may be introduced without thereby departing from the principle of the invention.

For example, in the event of higher loom speeds than those existing at present, the external face of the rigid part -of the resilient member could comprise longitudinal ribs in order to increase the heat dissipation surface.

What I claim is:

1. In a weft inserting device for a loom in which the weft is supplied from a stationary source, a clamping member consisting of a rigid member and a resilient member having at one end a foot portion secured iiat against said rigid member and a rigid portion having at its end a clamping zone for clamping the weft thread, said resilient member being rigid over the greater portion of its length and having an intermediate llexible portion of relatively short length extending between said rigid portion and said end foot portion.

2. The clamp as deiined in claim 1, wherein said end foot portion of said resilient member is rigid.

3. The clamp as defined in claim 1, wherein said intermediate exible portion of said resilient member has a thickness smaller than the thicknesses of said foot portion and said rigid portion.

4. A clamp in accordance with claim 3, where-in said resilient member includes two short slanted portions, and

wherein the face of said intermediate flexible Yportion of y v responding face of said rigid portion of said resilient mem- References Cited by the Examiner UNITED STATES PATENTS 9/1951 Dewas 139-122 2/1960 Dewas 139-122 MERVIN STEIN, Primary Examiner.

H. S. JAUDON, Assistant Examiner. 

1. IN A WEFT INSERTING DEVICE FOR A LOOM IN WHICH THE WEFT IS SUPPLIED FROM A STATIONARY SOURCE, A CLAMPING MEMBER CONSISTING OF A RIGID MEMBER AND A RESILIENT MEMBER HAVING AT ONE END A FOOT PORTION SECURED FLAT AGAINST SAID RIGID MEMBER AND A RIGID PORTION HAVING AT ITS END A CLAMPING ZONE FOR CLAMPING THE WEFT THREAD, SAID RESILIENT MEMBER BEING RIGID OVER THE GREATER PORTION OF ITS LENGTH AND HAVING AN INTERMEDIATE FLEXIBLE PORTION OF RELATIVELY SHORT LENGTH EXTENDING BETWEEN SAID RIGID PORTION AND SAID END FOOT PORTION. 